A known brake actuation system has hydraulic connections between the braking pressure generators and the master brake cylinder which are closed by operation of the solenoid operated separating valves, the closing of which are delayed with respect to pedal actuation. Low-pressure accumulators which are connected to the wheel brakes in the release position of the braking pressure generators, are connected to the pressure chambers of the braking pressure generators. In particular in the event of quick actuation, the response time is shortened and the dynamic behavior of the system is enhanced.
A disadvantage of this known brake actuation system is that due to different actuation speeds, the fluid volume which is furnished for rapid prefilling of the wheel brakes from the master brake cylinder through the separating valves, is not exactly defined after the time-controlled closing of the separating valves, on the one hand. Thus, the fluid volume supplied by the braking pressure generators does not provide an indication of the pressure prevailing in the wheel brakes. On the other hand, the separating valves remain open for the predetermined period even at slow actuation speeds. This is detrimental to the pedal feeling. Further, providing the low-pressure accumulators necessitates great structural efforts.